Pontoon unit for endless tracks



March 9, 1965 E. M. TUCKER, SR

PONTOON UNIT FOR ENDLESS TRACKS 2 Sheets-Sheet 1 Filed Aug. 19, 1963 Z a w W W .H my 7 W E w m A mv Q Q x. R MN Q on 7 mw MN \\N@/ MN m a a \N & a u s a M a a. a w N m Q\ m w\ mm mm mm mu 0 m RN & mm \m m mm m k & m m @N m\ km MN mm o o W\ NM. bN um. o G 0 \w 0 o MN m Q N. m R W F i March 9, 1965 E. M. TUCKER, SR

PONTOON UNIT FOR ENDLESS TRACKS 2 Sheets-Sheet 2 Filed Aug. 19 1963 IIIIIIIIIII'!IIIIII| ,IIIIIII/ll'iliIIIIIII!!!II!It!!!llllIIIIlI/IIIIIIII I,

United States Patent O ice 3,172,767 Patented Mar. 9, 1%65 3,172,707 PQNTGON UNIT FGR ENDLESS TRACKS Emmitt M. Tucker, Sn, Medford, Greg, assignor to Tucker & Sons, Grass Valley, Califi, a corporation of California Filed Aug. 19, 1963, Ser. No. 393,059 3 Claims. (Cl. 305-18) This invention relates in general to the supporting units for endless tracks such as are used on tractors and similar vehicles, and is directed particularly to a pontoon unit such as forms part of a snow traversing vehicle now on the market and commercially known as a Sno-Cat. Such pontoon units, of the general type, are shown in sundry previously issued patents, such as United States Patent No. 2,561,716, dated .iuly 24, 1951.

Heretofore, the pontoons, and the endless track engaging elements thereof, have always been made of steel or like heavy metal, and their total weight has been considerable and such as to cause the vehicle to sometimes bog down as, for example, when traversing light or powdery snow.

It is, therefore, the major object of the present invention to provide a pontoon unit, for the purpose described, wherein the body is made of a material such as rigid Fiberglas or similar plastic material which is relatively light compared to steel; there being, on such body, an endless traek engaging structure of wear resistant material such as steel or the like.

Such track engaging structure is made. up of a number of separate metallic parts, and a further object of the invention is to attach these parts to the pontoon body in a manner such that any or all such parts may be readily removed and replacedif necessary and due to damage or wear-without interfering with any of such parts that are not removed, and without affecting the pontoon body in any manner.

An additional object of the invention is to provide a pontoon unit which, while including a body of rigid Fiberglas or similar plastic material, is strong, durable and capable of withstanding hard usage.

A further object of the invention is to provide a pontoon unit for endless tracks which is designed for ease and economy of manufacture.

A still further object of the invention is to provide a practical and reliable pontoon unit for endless tracks, and one which is exceedingly etlective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings:

FIG. 1 is a side elevation of the improved pontoon unit, showing a fragmentary portion of the endless track thereon.

FIG. 2 is a longitudinal sectional elevation of the pontoon unit.

FIG. 3 is a cross section taken on line 33 of FIG. 2.

FIG. 4 is a fragmentary sectional plan view taken on line 4-4 of FIG. 1.

FIG. 5 is a fragmentary top plan view of the pontoon unit.

FIG. 6 is a fragmentary cross section on line 66 of FIG. 1.

Referring now more particularly to the drawings and to the characters of reference marked thereon, the pontoon, as herein depicted, is generally of the same shape as that shown in United States Patent No. 2,984,522 and cornprises, in the main, an elongated Watertight body indicated generally at 1, and specifically made of molded Fiberglas or similar plastic material.

T he body includes generally identical inner and outer side walls 2 and 3, respectively, which are connected together in integral relation by a transverse wall W which includes a straight bottom portion 4 merging into rounded end portions 5 which in turn merge into top portions 6 separated from each other for a certain distance at the central longitudinal portion of the pontoon, as clearly shown in FIG. 2.

Another continuous wall 7 is formed with and extends between the side walls 2 and 3, and depends from the adjacent ends of the top wall portions 6; said wall 7 forming a well 8, between the side walls 2 and 3, in which the drive sprockets (not shown) for the endless track links 9 are disposed. The wall 7 is also formed at the bottom with a drain trough in having openings 11 therefrom in the corresponding portions of the side walls 2 and 3. The inner side Wall 2 is formed with a circular bushed opening 12 adjacent the top of the well 8 and centrally of the width thereof to receive the supporting sprocket-shaft housing of the pontoon-supported vehicle; the shaft itself projecting from said housing in journaled relation through an opening 13 in the side wall 3 and being enclosed by a cover plate 14 for such opening, These features are essentially shown in United States Patent No. 2,561,716 and form no part of the present invention, which is directed to the construction of the pontoon unit itself.

Irrespective of the exact arrangement of the above noted parts, it will be obvious that the greatest strains are applied to the pontoon about the side wall openings 12 and 13. To aid the pontoon in withstanding such strains, the side walls 2 and 3 are formed with a plurality of elongated ribs 15 projecting radially of and about the openings 12 and 13 in the form of a sunburst. These ribs 15, which obviously reinforce the relatively thin side walls, project from the outer faces of said side walls, and taper in width and depth to their outer ends as shown.

The endless track links 9 include rollers 16 at their opposite sides adapted to engage supporting and guiding tracks on and extending about the pontoon. To this end, and so that the rollers will ride on surfaces which have greater wear-resisting qualities than the Fiberglas of the pontoon body 1, the following removable track or rail arrangement is provided.

Extending along the straight bottom portion of the pontoon on each side thereof is a channel shaped out wardly facing rail 17 of a width and depth to contain the track rollers 16, and including top and bottom flanges 13 and 19, respectively. The top flange 18 is provided along its outer edge and at spaced intervals in its length with upstanding cars 20 which are secured to the adjacent pontoon side Wall by studs 21 mounted in and projecting from the side walls, and engaged on their outer ends by detachable nuts 22.

Each rail 1'7 is full recessed into the adjacent side wall of the pontoon as shown at 23 in FIG. 3; this recess being of right angle form and facing both vertically and horizontally and extending for the full peripheral extent of the pontoon. The inner or back wall 24 of the recess, beyond the ends of the rail 17, is flush therewith.

Extending about each rounded end portion of the pontoon, and following the contour thereof and ofthe correspondingly shaped recess 23 on each side of the pontoon, is a roller-engaging rail-forming flange 25, alined at its lower end with and terminating close to the corresponding end of the upper flange 13 of the rail 17. This flange 25 is provided, along the central portion of its extent, with a flap plate 26 which extends lengthwise of the pontoon and overlies and bears against the adjacent portion of the adjacent sidewall of said pontoon. The plate 26 is formed with longitudinal vertically spaced slots 27 into which bolts 28 project; said bolts being secured in the adjacent side wall or" the pontoon and include clamping nuts 29 engaging said plate. Similar but smaller plates 3i) are also disposed adjacent the ends of each rail flange 25, and bear against the adjacent side wall of the pontoon. The plates 39 are formed with slots 31 which extend generally lengthwise of the pontoon; these slots being engaged by pontoon-mounted clamping bolts 32. This arrangement of plates and clamping bolts enables the rail flange 25 to be moved a limited distance lengthwise of the pontoon and to be then held in any position of adjustment; the purpose, of course, being to adjust the tension of the endless track which extends about the pontoon.

In order to effect such adjustment, the plate 26 is formed with an outwardly projecting lug 33 through which an adjusting bolt 3 projects; said'bolt extending lengthwise of the pontoon, and at its end beyond the plate 26 engaging against the facing end of a stop 35 formed on and projecting outwardly from the adjacent side wall of the pontoon.

Each rai flange 25 at its upper end delivers, at the same level, onto the adjacent end of another roller-supporting rail-forming flange 36. The flange 36 rests on the corresponding bottom portions of the pontoon recess 23, and extends continuously and across the well 8 to a termination adjacent and in line with the upper end of the other rail flange 25 on the same side of the pontoon, as clearly shown in FIG. 1. At intervals in its length,

the flange 36 is provided along its outer edge with depend- -ing ears 37 which flatly engage the adjacent side wall of the pontoon and are secured thereto by pontoon-mounted bolts 38.

Centrally of its ends, and for the extent thereof which crosses the well 8, the flange 36 forms the bottom flange of an upstanding outwardly facing roller engaging and confining channel 39, the ends of the back wall 49 of which abut against the ends of the pontoon recess 23, where such recess terminates at the well 8; said back wall at? being flush with the back wall 24 of the recess, as indicated in FIG. 5. The upper flange 41 of the channel 39 extends for some distance beyond the ends of the channel so as to overlie the transverse wall portion 6 of the pontoon beyond the well 8 as shown. Such overlying portions of the flange 41 are formed with cars 42 which project laterally from said flange and are secured to the pontoon wall 6 by bolts 43. This last described rollerengaging channel arrangement, besides reinforcing the pontoon in the zone of the well 8, provides the necessary positive locating means for the track links 9 as they pass across and are engaged by the sprockets in the well and the rollers of which track links are than closely engaged between the upper and lower flanges 36 and 41, respectively, of such channels 39. i

It is to be noted that all the various ears 2% and 37, as well as the plates 26 and 30, are disposed in shallow recesses 44 formed in the side walls of the pontoon, so that said ears and plates are flush with the outer faces of said side walls and are thus not exposed laterally out from the pontoon where they might be contacted and possibly dislodged or distorted by obstructions in the path of movement of the pontoon.

In order to prevent the bottom wall 4 of the pontoon from being abraded and worn by contact with the terrain material over which the pontoon unit passes, a wear plate or shoe 45 extends between the rails 17 for the full length thereof and in contact with said bottom wall 4; said wear plate 45 being flush with the lower flanges 19 of the rails 17 as shown in FIG. 3.

Rigddly secured to and extending along and under the plate 45 centrally of its width is a shock or safety rail 4s, shaped so as to stiffen said plate against possible bending in a longtudinal direction. This shock rail' ifi is formed with extensions 47 which project about the upwardly curving transverse end wall portions 5 of the pontoon to a point about midway of its height as shown. The extensions 47 we formed with base flanges 43 which follow the contour of and abut against said wall portions 5, and which extensions are secured at intervals to said wall portions 5 by detachable bolts 49.

The various rails, together with the wear plate and shock rail, are made of Wear resistant steel or other metal, and may be independently removed from the pontoon should they become damaged, or unduly worn, and require replacement. Also, of course, the use of metal for the parts of the pontoon unit most susceptible to wear enables the pontoon itself to be made of the much lighter plastic material Without loss of efiiciency while affording to the pontoonunit the advantages in operation attained by the lighter overall weight.

From the foregoing description, it will be readily seen that there has been produced such a device as substantially fulfills the objects of the invention, as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described the invention, the following is claimed as new and useful and upon which Letters Patent is desired:

1 claim:

1. A pontoon unit for an endless track, the unit comprising a pontoon body formed of plastic material, said pontoon body including side walls having substantially straight bottom edges and upwardly rounded end edges,

and a transverse wall extending about the periphery of the side walls; a rail structure for engaging and supporting the endless track, said rail structure being mounte .on and extending about the periphery of the pontoon at the sides thereof, a bottom wear plate extending along and engaging the bottom portion of the transverse wall for the full length and width of such portion between the adjacent portions of the rail structure, and means removably mounting the plate on the pontoon; said means comprising a shock rail secured on and extending along the wear plate intermediate the side edges thereof in depending relation to said plate; said shock rail including extensions projecting from both ends of the wear plate and engaging the adjacent parts of the rounded end portions of the transverse wall, and bolts removably securing the extensions to said transverse wall portions.

2. A pontoon unit for an endless track which includes a plurality of transversely spaced links each having a projecting horizontal-axis roller, the unit comprising a pontoon which includes side walls and a transverse wall extending about the periphery of the side walls, means between the side walls forming a Well within the pontoon open to the top thereof and arranged to contain track engaging and driving members, the pontoon being formed 011 each side with a continuous peripherally extending recess of angular form in section and facing both horizontally and vertically, and a metal rail structure for engaging and supporting the track rollers mounted in and extending about each recess for the full length thereof; said rail structure comprising a roller-receiving channel having an upper flange extending along the bottom portion of the recess, means removably mounting the channel on the pontoon, a roller-engaging rail extending about each end of the pontoon within the recess and flush at its lower end with the adjacent end of the upper flange of the channel, means removably mounting each such rail on the pontoon While providing for longitudinal adjustment thereof, another roller supporting rail mounted within the upper portions of the recess at the bottom thereof and extending the full length of the pontoon between the adja cent ends of the adjustable rails and flush therewith, means removably mounting the last named rail at spaced points in its length on the adjacent side wall of the pontoon, and a roller-confining channel having an upper flange upstanding from said last named rail for the longitudinal extent of the well and of which channel such rail forms the bottom flange.

3. A pontoon unit, as in claim 2, in which the upper flange of the last named channel is formed with extensions overlying the adjacent portions of the recess and parallel to said last named rail, ears on the extensions projecting laterally inward and resting on the top of the pontoon laterally in from the recess, and bolts removably securing the ears to the pontoon.

References Cited by the Examiner UNITED STATES PATENTS 2,483,961 10/49 Ball 30516 X 2,561,716 7/51 Tucker 30518 2,974,390 3/61 Nelson 27--7 2,984,522 5/61 Tucker et al. 30517 X 3,023,431 3/62 Applegate 9 2 3,065,574 11/62 Piana 50268 FOREIGN PATENTS 843,264 3/ 39 France.

ARTHUR L. LA POINT, Primary Examiner. 

2. A PONTOON UNIT FOR AN ENDLESS TRACK WITH INCLUDES A PLURALITY OF A TRANSVERSELY SPACED LINKS EACH HAVING A PROJECTING HORIZONTAL-AXIS ROLLER, THE UNIT COMPRISING A PONTOON WHICH INCLUDES SIDE WALLS AND A TRANSVERSE WALL EXTENDING ABOUT THE PERIPHERY OF THE SIDE WALLS, MEANS BETWEEN THE SIDE WALLS FORMING A WELL WITHIN THE PONTOON OPEN TO THE TOP THEREOF AND ARRANGED TO CONTAIN TRACK ENGAGING AND DRIVING MEMBERS, THE PORTION BEING FORMED ON EACH SIDE WITH ACONTINUOUS PERIPHERALLY EXTENDING RECESS OF ANGULAR FORM IN SECTION AND FACING BOTH HORIZONTALLY AND VERTICALLY, AND A METAL RAIL STRUCTURE FOR ENGAGING AND SUPPORTING THE TRACK ROLLERS MOUNTED IN AND EXTENDING ABOUT EACH RECESS FOR THE FULL LENGTH THEREOF; SAID RAIL STRUCTURE COMPRISING A ROLLER-RECEIVING CHANNEL HAVING AN UPPER FLANGE EXTENDING ALONG THE BOTTOM PORTION OF THE RECESS, MEANS REMOVABLY MOUNTING THE CHANNEL ON THE PONTOON, A ROLLER-ENGAGING RAIL EXTENDING ABOUT EACH END OF THE PONTOON WITHIN THE RECESS AND FLUSH AT ITS LOWER END WITH THE ADJACENT END OF THE UPPER FLANGE OF THE CHANNEL, MEANS REMOVABLY MOUNTING EACH SUCH RAIL ON THE PONTOON WHILE PROVIDING FOR LONGITUDINAL ADJUSTMENT THEREOF, ANOTHER ROLLER SUPPORTING RAIL MOUNTED WITHIN THE UPPER PORTIONS OF THE RECESS AT THE BOTTOM THEREOF AND EXTENDING THE FULL LENGTH OF THE PONTOON BETWEEN THE ADJACENT ENDS OF THE ADJUSTABLE RAILS AND FLUSH THEREWITH, MEANS REMOVABLY MOUNTING THE LAST NAMED RAIL AT SPACED POINTS IN ITS LENGTH ON THE ADJACENT SIDE WAY OF THE PONTOON, AND A ROLLER-CONFINING CHANNEL HAVING AN UPPER FLANGE UPSTANDING FROM SAID LAST NAMED RAIL FOR THE LONGITUDINAL EXTENT OF THE WELL AND OF WHICH CHANNEL SUCH RAIL FORMS THE BOTTOM FLANGE. 